(-2a)*(3a^2-4a-1)-a(-6a^2+5a-2)=-6a^3+8a^2+2a+6a^3-5a^2+2a=3a^2+4a当a=-1得-1
:(-2a).(3a的平方-4a-1)-a(-6a的平方+5a-2),=-6a³+8a²+2a+6a³-5a²+2a=3a²+4a=3-4=-1
因为原式=3a²+4a 把a=-1代入得-1
= -2a-(5a-1)-a(41a-2)把a=-1带入-3a+1-a(41a-2)=3+1-43=-39